It was shown for the Kawahara equation that in the TDSW regime the resonant wavetrain is linked to the level \(u_{+}\)  ahead
by a partial DSW [1]}. A partial DSW is a modulated wavetrain which takes a uniform wavetrain down to a constant level,
in contrast to a full DSW which is a modulated wavetrain which connects two uniform levels [2]}, [3]}.
As stated, a negative polarity solitary wave connects the resonant wavetrain to the level \(u_{i}\)  behind [4]}. As
there is no known solitary wave solution of the Kawahara equation of either polarity, this connection was done numerically
and by using approximate theory in previous work [4]}, [1]}. However, it has been recently realised that the determination
of this connecting negative polarity solitary wave is not necessary [7]}. The connection between the resonant wavetrain
and the level behind can be treated as a Whitham shock, the wavetrain equivalent of a gas dynamic shock, for the Whitham modulation
equations governing the resonant wavetrain, confirming speculation by Whitham when he originally developed modulation theory
[8]}, [9]}. This shock-like nature of the connection can be seen for the nematic TDSW illustrated in Figure
REF , where the discontinuous connection between the resonant wave and the uniform level behind is clearly visible.
